diff --git a/java/java-psi-api/src/com/intellij/psi/util/PsiUtil.java b/java/java-psi-api/src/com/intellij/psi/util/PsiUtil.java
index 1c98cf154a09..bf62af9e729d 100644
--- a/java/java-psi-api/src/com/intellij/psi/util/PsiUtil.java
+++ b/java/java-psi-api/src/com/intellij/psi/util/PsiUtil.java
@@ -1212,7 +1212,7 @@ public final class PsiUtil extends PsiUtilCore {
     return expression;
   }
 
-  public static PsiElement skipParenthesizedExprUp(PsiElement parent) {
+  public static PsiElement skipParenthesizedExprUp(@Nullable PsiElement parent) {
     while (parent instanceof PsiParenthesizedExpression) {
       parent = parent.getParent();
     }
diff --git a/plugins/java-i18n/src/com/intellij/lang/properties/PrefixBasedPropertyReference.java b/plugins/java-i18n/src/com/intellij/lang/properties/PrefixBasedPropertyReference.java
index cc0afcc4428f..ea49588fb8e5 100644
--- a/plugins/java-i18n/src/com/intellij/lang/properties/PrefixBasedPropertyReference.java
+++ b/plugins/java-i18n/src/com/intellij/lang/properties/PrefixBasedPropertyReference.java
@@ -42,6 +42,7 @@ public class PrefixBasedPropertyReference extends PropertyReference {
     super(key, element, bundleName, soft);
   }
 
+  @Override
   @NotNull
   protected String getKeyText() {
     String keyText = super.getKeyText();
@@ -50,6 +51,7 @@ public class PrefixBasedPropertyReference extends PropertyReference {
     return keyText;
   }
 
+  @Override
   protected void addKey(Object property, Set<Object> variants) {
     String key = ((IProperty)property).getUnescapedKey();
     final String keyPrefix = getKeyPrefix();
diff --git a/plugins/properties/properties-psi-impl/src/com/intellij/lang/properties/references/PropertyReference.java b/plugins/properties/properties-psi-impl/src/com/intellij/lang/properties/references/PropertyReference.java
index 4c2d1e383170..4330395bf633 100644
--- a/plugins/properties/properties-psi-impl/src/com/intellij/lang/properties/references/PropertyReference.java
+++ b/plugins/properties/properties-psi-impl/src/com/intellij/lang/properties/references/PropertyReference.java
@@ -42,6 +42,7 @@ public class PropertyReference extends PropertyReferenceBase implements LocalQui
     myBundleName = bundleName;
   }
 
+  @Override
   @Nullable
   protected List<PropertiesFile> getPropertiesFiles() {
     if (myBundleName == null) {
@@ -54,6 +55,7 @@ public class PropertyReference extends PropertyReferenceBase implements LocalQui
     return I18nUtil.propertiesFilesByBundleName(bundleName, element);
   }
 
+  @Override
   public LocalQuickFix[] getQuickFixes() {
     List<PropertiesFile> propertiesFiles = retrievePropertyFilesByBundleName(myBundleName, getElement());
     LocalQuickFix fix = PropertiesQuickFixFactory.getInstance().createCreatePropertyFix(myElement, myKey, propertiesFiles);
diff --git a/plugins/properties/properties-psi-impl/src/com/intellij/lang/properties/references/PropertyReferenceBase.java b/plugins/properties/properties-psi-impl/src/com/intellij/lang/properties/references/PropertyReferenceBase.java
index a7659062b93b..306329525d1b 100644
--- a/plugins/properties/properties-psi-impl/src/com/intellij/lang/properties/references/PropertyReferenceBase.java
+++ b/plugins/properties/properties-psi-impl/src/com/intellij/lang/properties/references/PropertyReferenceBase.java
@@ -60,6 +60,7 @@ public abstract class PropertyReferenceBase implements PsiPolyVariantReference,
     myTextRange = range;
   }
 
+  @Override
   public PsiElement resolve() {
     ResolveResult[] resolveResults = multiResolve(false);
     return resolveResults.length == 1 ? resolveResults[0].getElement() : null;
@@ -70,6 +71,7 @@ public abstract class PropertyReferenceBase implements PsiPolyVariantReference,
     return myKey;
   }
 
+  @Override
   public boolean equals(final Object o) {
     if (this == o) return true;
     if (o == null || getClass() != o.getClass()) return false;
@@ -78,25 +80,30 @@ public abstract class PropertyReferenceBase implements PsiPolyVariantReference,
     return getElement() == other.getElement() && getKeyText().equals(other.getKeyText());
   }
 
+  @Override
   public int hashCode() {
     return getKeyText().hashCode();
   }
 
+  @Override
   @NotNull
   public PsiElement getElement() {
     return myElement;
   }
 
+  @Override
   @NotNull
   public TextRange getRangeInElement() {
     return myTextRange;
   }
 
+  @Override
   @NotNull
   public String getCanonicalText() {
     return myKey;
   }
 
+  @Override
   public PsiElement handleElementRename(String newElementName) throws IncorrectOperationException {
     /*PsiElementFactory factory = JavaPsiFacade.getInstance(myElement.getProject()).getElementFactory();
 
@@ -114,10 +121,12 @@ public abstract class PropertyReferenceBase implements PsiPolyVariantReference,
     /*}*/
   }
 
+  @Override
   public PsiElement bindToElement(@NotNull PsiElement element) throws IncorrectOperationException {
     throw new IncorrectOperationException("not implemented");
   }
 
+  @Override
   public boolean isReferenceTo(PsiElement element) {
     if (!isProperty(element)) return false;
     for (ResolveResult result : multiResolve(false)) {
@@ -135,15 +144,18 @@ public abstract class PropertyReferenceBase implements PsiPolyVariantReference,
     mySoft = soft;
   }
 
+  @Override
   public boolean isSoft() {
     return mySoft;
   }
 
+  @Override
   @NotNull
   public String getUnresolvedMessagePattern() {
     return PropertiesBundle.message("unresolved.property.key");
   }
 
+  @Override
   @NotNull
   public ResolveResult[] multiResolve(final boolean incompleteCode) {
     final String key = getKeyText();
@@ -168,7 +180,8 @@ public abstract class PropertyReferenceBase implements PsiPolyVariantReference,
     return getResolveResults(properties);
   }
 
-  protected static ResolveResult[] getResolveResults(List<IProperty> properties) {
+  @NotNull
+  private static ResolveResult[] getResolveResults(List<? extends IProperty> properties) {
     if (properties.isEmpty()) return ResolveResult.EMPTY_ARRAY;
 
     final ResolveResult[] results = new ResolveResult[properties.size()];
@@ -183,6 +196,7 @@ public abstract class PropertyReferenceBase implements PsiPolyVariantReference,
   @Nullable
   protected abstract List<PropertiesFile> getPropertiesFiles();
 
+  @Override
   @NotNull
   public Object[] getVariants() {
     return ArrayUtil.EMPTY_OBJECT_ARRAY;